Getting normal information from OpenGL render output

Posted by okamiueru on Stack Overflow See other posts from Stack Overflow or by okamiueru
Published on 2010-06-11T21:54:19Z Indexed on 2010/06/12 15:02 UTC
Read the original article Hit count: 181

Filed under:

opengl

|

fragment-shader

|

normals

I'll try to keep this simple.

I want a way to access the normal information of the scene, from the Frame Buffer output (or similar). The same way one is able to access the Depth Buffer using glGetTexImage and GL_DEPTH_COMPONENT.

I know I could set up a fragment shader which outputs the normal information in RGB color space, which could in turn be read from the rendered image. I'm wondering however if there is a way to do this within the openGL API.

I'll clarify anything upon request as best as I can, Thank you

© Stack Overflow or respective owner

Related posts about opengl

Unity completely broken after upgrade to 12.10?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am facing a very frustrating issue with my computer right now. I successfully upgraded to Ubuntu 12.10 this afternoon, but after the upgrade, the graphical user interface seems completely broken. To be more specific, I can not get the Unity bar to appear on the right. I have tried many things,… >>> More
OpenGL or OpenGL ES

as seen on Game Development - Search for 'Game Development'
What should I learn? OpenGL 4.1 or OpenGL ES 2.0? I will be developing desktop applications using Qt but I may start developing mobile applications in a few months, too. I don't know anything about 3D, 3D math, etc and I'd rather spend 100 bucks in a good book than 1 week digging websites and going… >>> More
OpenGL ES 2/3 vs OpenGL 3 (and 4)

as seen on Game Development - Search for 'Game Development'
I have migrated my code from OpenGL ES 2/3 to OpenGL 3 (I added bunch of defines and abstract classes to encapsulate both versions, so I have both in one project and compile only one or another). All I need to change was context initialization and glClearDepth. I dont have any errors. This was kind… >>> More
OpenGL extension vs OpenGL core

as seen on Programmers - Search for 'Programmers'
I was doubting: I'm writing a cross-platform engine OpenGL C++, I figured out windows forces the developers to access OpenGL features above 1.1 through extensions. Now the thing is, on Linux, I know that I can directly access functions if the version supports it through glext.h and opengl version… >>> More
LWJGL - Eclipse error [on hold]

as seen on Game Development - Search for 'Game Development'
When I try to run my lwjgl project, an error pops . Here is the log file: # A fatal error has been detected by the Java Runtime Environment: # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x6d8fcc0a, pid=5612, tid=900 # JRE version: 6.0_16-b01 Java VM: Java HotSpot(TM) Client VM (14.2-b01 mixed… >>> More

Related posts about fragment-shader

cocos2d fragment shader transparency

as seen on Game Development - Search for 'Game Development'
I'm playing with custom fragment shaders for a CCSprite (see http://www.raywenderlich.com/4428/how-to-mask-a-sprite-with-cocos2d-2-0). But I can't figure out why I get a white color whith the following line: gl_FragColor = vec4(1.0,1.0,1.0,0.0); Whereas I have a transparent color with this: gl_FragColor… >>> More
Fragment Shader Eye-Space unscaled depth coordinate

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to use the unscaled (true distance from the front clipping plane) distance to objects in my scene in a GLSL fragment shader. The gl_FragCoord.z value is smaller than I expect. In my vertex shader, I just use ftransform() to set gl_Position. I'm seeing values between 2 and 3 when I expect… >>> More
shader coding: calculate screen coordinates of fragment

as seen on Game Development - Search for 'Game Development'
Good morning, I'm new to shader coding and trying to implement some visual effects code in shaders using billboards. (Yes, I couldn't have picked anything harder to start with, but I'm lucky that way) Setup: I have rendered the full screen z depth to an array of floats in a previous pass. In the… >>> More
OpenGL ES 2.0: Vertex and Fragment Shader for 2D with Transparency

as seen on Game Development - Search for 'Game Development'
Could I knindly ask for correct examples of OpenGL ES 2.0 Vertex and Fragment shader for displaying 2D textured sprites with transparency? I have fairly simple shaders that display textured polygon pairs but transparency is not applied despite: texture map contains transparency information Blending… >>> More
OpenGL ES Basic Fragment Shader help with transparency

as seen on Game Development - Search for 'Game Development'
I have just spent my first half hour playing with the shader language. I have modified the basic program I have which renders the texture, to allow me to colour the texture. varying vec2 texCoord; uniform sampler2D texSampler; /* Given the texture coordinates, our pixel shader grabs the corresponding … >>> More